Thermal expansion and its impacts on thermal transport in the FPU-α-β model

We study the impacts of thermal expansion, arising from the asymmetric interparticle potential, on thermal conductance in the FPU-alpha-beta model. A nonmonotonic dependence of the temperature gradient and thermal conductance on the cubic interaction parameter alpha are shown, which corresponds to the variation of the coefficient of thermal expansion. Three domains with respect to alpha can be identified. The results are explained based on the detailed analysis of the asymmetry of the interparticle potential. The self-consistent phonon theory, which can capture the effect of thermal expansion, is developed to support our explanation in a quantitative way. Our result would be helpful to understand the issue that whether there exist normal thermal conduction in the FPU-alpha-beta model. C 2015 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License.